Fuel injection system



Om. OM Om Y N\\ h. o/AM, fwn Mh Sept. 29, 1953 Filed sept. 18, 1951Sept. 29', 1953 c. R. ALDEN FUEL INJECTION SYSTEM 2 Sheets-Sheet 2 FiledSept. 18, 1951 ne.V co2 new OOM. m 00N lillIJk m ook :L Vllllllllllllllllllllllllll l.. ou? N om* n o@ DQ OQ ok om o Pn um 9 on0. o a ot QQ UQQ QWLK OQ# WKOLUQ INVENTOR CA RROLL Patented Sept. 29,1953 UNITED STATES PATENT OFFICE American Bosch Corporation,

Springfield,-

Mass., a corporation of New York Application September 18, 1951, SerialNo. 247,079

(Cl. 12S-32) 8 Claims.

This invention pertains to an improvement in systems for timed meteredinjection of fuel as used in connection with internal combustionengines. Such a system was disclosed in U. S. Patents Nos. 2,527,36;2,069,744; 2,075,949; 2,202,- 510; 2,223,5Sl and included means foropening and closing the several injection nozzles by unbalance ofhydraulic pressure applied upon opposits ends of reciprocable valveoperating plunger,

The earlier patented system includes a rotary distributing valve forcontrolling the application of valve actuating pressures sequentially onthe several injection nozzles. Such rotary valves present the hazardthat stickage of the single rotary member may cause failure of fuelinjection from a plurality of injection nozzles contrlled by theassociated distributor. It is an ob ject of this invention to avoid thathazard.

In the earlier patented system the means controlling the application ofhydraulic pressure for actuating the several injection nozzles includedno readily alterable adjustment for increasing or decreasing thequantity of fuel delivered from one nozzle independently of all others.It is an object of this invention to provide such a fuel quantityadjustment.

In the earlier patented system the means controlling tne application ofhydraulic pressure for actuating the several injection nozzles includedno readily alterable adjustment for advancing or retarding the start ofinjection from one nozzle independently of the other nozzles. It is anobject of this invention to provide such a nozzle timing adjustment.

A further object of this invention is economically 'to provide a sourceof fuel under a constant pressure intermediate atmospheric pressure andthe total fuel injection pressure but of magnitude predeterminedlyrelated to the latter for use in controlling the action of the fuelinjection nozzles.

A still further object is economically to insure complete cessation ofinjection when desired Without such Waste of fuel pressure energy as washeretofore encountered in relieving the fuel injection tubing ofpressure following each pressure application thereto particularly Whencalling for the injection of smaller or zero quantities of fuel percycle.

Referring to Fig. l I provided a nozzle body i including an axial bore 2formed at one extremity with a valve seat 3 which by coaction with avalve.

plunger `Il reciprocable in the bore 2 is adapted to duit 5 to a nozzledischarge orifice 6 which may be single or multiple, annular or of anyform suited to the fuel spray characteristics favorable to theassociated engine (not shown). In the open position of valve 3 theentire and area of the plunger 4 which is then exposed to the pressureof fuel in conduit 5 is effective to urge the plunger toward itsopenmost position. In its seated or closed position that area encircledby the seat 3, which, illustratively, may Well be approximately onefifth of the total end area of the plunger, is not exposed to fuelpressure and, neglecting such relatively insignificant pressure as maybe applied by engine cylinder gases beneath the seat 3, the force,according to the present example, which is applied to lift the valvefrom the closed position may be reckoned as 4/5A P Where A representsthe total area of the valve plunger and P the pressure of the fuel insupply conduit 5. After the valve 4 has lifted from its seat 3 the forcetending to hold the valve open is A P. A cut-oilE valve later to bedescribed is adapted alternatively to admit fuel at pressure P to theremote end of conduit 5 or to cut off such communication. When so cutoff conduit 5 is without opening unless plunger 4 opens valve seat 3.

Though the valve plunger 4 may be biased t0- Ward its closed position bya spring, not shown, such is not essential. The end of Valve plunger klopposite that which coacts with seat 3 is of area A and under allcircumstances is acted upon by the pressure of'fuel in a control conduit'I which is in constant communication therewith. The pressure applied onthe remote end of conduit 'l and therefore on this end of the plunger 4is alternated, by a distributor valve presently to be described, betweenthe full injection pressure P and, according to this example, anintermediate pressure of approximately 2/3P.

The forces tending to move plunger 4 toward its seated position are thusseen to alternate between A P and 2/3A. P.

It may now be seen that an any time the remote end of conduit 5 becomescut off from the supply of fuel at pressure P even the minimum availableforce of %A P acting to move valve 4 toward its yclosed position will beeffective to do so and injection of fuel from orifice 6 will promptly beout off by closure of valve 3.

It may also be seen that, so long as the full fuel pressure P is appliedto the remote end of conduit 'l the force effective to close valve 3 isA P. it therefore follows that so long as Valve 3 is closed', full Vfuelpressure P may be applied to the remote end of conduit without liftingplunger 4 as the effective opening force then is but 4/5A P which isless than the closing force AXP; however, upon applying the alternativeintermediate pressure 2/aP to the remote end of conduit I the closingforce at once crops to 2,A P which, being less than /SAXP, allows piston4 immediately to move to that position which opens valve 3 and initiatesinjection of fuel.

Summarizing: In each cycle of operation full fuel pressure P is appliedto the remote end of conduit 'I an appreciable time before initiation offuel injection is desired. At a later time, but still appreciably beforeinitiation of injection is desired, full fuel pressure P is applied tothe remote end of fuel injection conduit 5.

To initiate fuel injection the remote end of conduit is alternated fromcommunication with the source of full fuel pressure P to an intermediatepressure 2/3P. This unbalances the forces which have held plunger 4 inits valve closing position and valve seat 3 lifts exposing the fulllower area A to the fuel pressure P.

To .terminate injection the remote end of injection conduit 5 is cut offfrom the source of fuel pressure. There is thereafter no force effectiveto hold piston 4 and valve 3 in open position and the opposed force of2/3AXP .acts immediately to close the valve. Note that in closing theplunger II acts as a pump plunger to inject its displacement volume at apressure 2/3P. At any convenient time in the cycle subsequently toclosing the valve 3 the pressure applied to the remote end of conduitmay be alternated to the full pressure P without other incident and atany convenient time between this last and the initiation of the nextinjection the remote end of fuel in jection conduit 5 may be connectedto full fuel pressure P Without incident thus completing preparation forthe next injection.

In practice I prefer to maintain the durations of alternative conditionson conduits 5 and 'I of fixed durations in relation to the length of onecomplete cycle of valve operations but to vary the phase relation of thecyclical occurrences affecting these respective conduits to effect ad-Vance or retard of the peint in the cycle at which injection isinitiated and to variably control the duration of injection between thelimits of zero and the maximum permissible.

In Fig. 2 the times before and after top dead center (TDC) have beenexpresed in degrees of engine crank travel as for a two stroke cycleengine, dotted curve IDO-460 represents the magnitude and timing of onecondition of pressure applications, as in conduit '1, which continuouslybut with varying force influence plunger 4 toward its valve closingposition. Curve SOi-SSII represents one condition of pressureapplication, as on conduit 5, which influences plunger 4 toward itsvalve opening position. The occurrence of pressure reduction on conduitI at point A which here occurs 5 before TDC denotes an unbalance offorces on plunger 4 which initiates injection at this point in theengine cycle and the occurrence of cut off of fuel supply at the remoteend of conduit 5 as at point B, which here takes place 15 after TDC,denotes termination of injection at that point in the engine cycle.

The greater the number of degrees by which the point B lies to the rightof point A, the greater the duration of injection. This may becontrolled by means to be shown. By this last means curve 50B-800 may beshifted bodily with respect to curve IDD-400 without altering the formof either. In like manner if point B be caused to come earlier in thecycle than point A, or to fall to the left of point B on the diagram ofFig. 2, a condition of absence of injection is indicated. Means alsowill later be shown whereby both curves IDD-400 and 590-300 may beshifted bodily in relation to TDC and without disturbing their mutualrelation. This denotes an advance or retard of injection with respect tothe engine cycle without altering the duration (or quantity) of fuelinjected.

At I0 in Fig. 1 is shown a drive shaft running at equal speed with thecrank of the associated (two stroke cycle) engine. To enable phase shiftof events A and B with respect to TDC (Fig. 2) cam shaft I3 is drivenfrom shaft Ic through a well known phase change coupling I! under thecontrol of means I2. The cams II on shaft I3, which is rotatable inbearings I4 may, through adjustable tappets I5 give reciprocation tovalves I6 for the purpose of alternating the hydraulic pressures appliedon the so-called remote ends of fuel control conduits 1 by which, whenthis pressure suffers reduction as at point A in Fig. 2, injection offuel from the associated nozzle is initiated. Though only one valve I6is detailed one for each engine cylinder is provided and each, by properpositioning of its actuating cam Il on shaft I3, closely co-ordinatesthe valve movements with the piston movements of the associated enginecylinder. This co--Crdnation may be more exactly determinable byadjustment of .the tappets I5.

Specifically control means I2 permits all timed functions of the entireinjection system to occur earlier or later in respect to events of theengine cycle (such as TDC of a reference piston) without altering theduration of .the injection period.

To permit the valves I6 to operate at high reciprocating speeds withoutrequiring excessive return force as by spring pressure to insure thatthe valves and their tappets will follow the cams, I prefer .that thecams shall closely approximate simple eecentrics which impart to thevalves a substantially harmonic reciprocation. By so doing theapplication of fuel pressure on the upper ends of the valve stems mayexert sufficient force to eliminate the necessity for valve returnsprings.

Each of the several valves I6, of which there are one for each enginecylinder served by the injection system, reciprocates in a co-actingbore I9 in a block I9a. The bores I9 are open at their upper orinnermost ends to the full fuel pressure P applied through a passage I8.Spaced from the passage I8 is a second parallel passage IBa intersectingall bores I9 which is continuously open to fuel at an intermediatepressure such as 2/3P. Intermediate these parallel passages the plungerbore I9 which receives valve I6 is recessed as at 20, the so-calledremote ends of conduits I are connected respectively to these recesses.The upper ends 2I of valves I6, for a length substantially equal to orbut slightly greater than the axial length of recesses 20, are a closefit in their surrounding bores. Below the end lportions 2| the valves I6have a portion 22 of reduced diameter, When the lower edge of head endportion 2I of any valve I6 is above the lower end of its co-actingrecess 20 the associated conduit I communicates reduced pressure, as at2/3P, to be applied on associated nozzle plunger 4 to urge it towardclosed position. When the upper edge of end portion 2l is below theupper end of recess conduit 'I communicates full fuel pressure P to besimilarly applied on plunger 4.

As I prefer that the change from one to the other of the two pressuresyalternatively applied to conduit 'l shall take place as rapidly as maybe, I prefer to cause this change to occur when the movement of thevalve is taking place at its highest velocity or approximately at themid point of its strokes. This also causes the change in eventsaccomplished by this valve to be separated from each other byapproximately l8u of engine crank travel as indicated on Fig. 2.

A second set of plain cylindrical valves 30 are similarly reciprocatedin bores 3l formed in block or body 32. A conduit 33, similar to conduitIt connects the upper ends of these bores continuously to full fuelpressure P. The bores 3l are formed with a recess 34 similar to therecess 20 spaced from their upper ends. The recesses 34 lare constantlyin communication with conduits 5. When the upper edge of any valve 30 isbelow the upper edge of recess 34 fuel under full pressure P howsthrough conduit 5 to be injected from orifice E subject to the controlof valve 3 as previously described. I prefer that this communicationshall be established while valves 30 are substantially midway of theiroutward strokes and cut off at substantially the same `point on theirinward strokes as indicated in Fig. 2.

Valves 30 are reciprocated by adjustable tappets 38 acted upon by cams35 on a shaft 36 which rotates in bearings 3l'. To permit the phase ofthe valving events occasioned by valves 3B all to be simultaneouslychanged with respect to those of valves I6 for the purpose ofcontrolling the duration and thereby the quantity of fuel injected percycle as set forth in the discussion of Fig, 2, shaft 35 is driven fromshaft I3 through a second phase change coupling 39 which may becontrolled by means 463. Tappet adjustment means I5a permits the eventsof an associated valve to be advanced or retarded independently of allothers as for minute correction of the duration of injection ofindividual nozzles.

A fuel pump |50 of any suitable construction may be arranged to drawfuel from a tank IIiI through a conduit m2 delivering the same underpressure P through conduit |03 to the passages I8 and 33 respectively ofvalve blocks I9@ and 32.

A conduit H34 joins high pressure fuel passages IS and 33. A branch H35from this conduit supplies fuel at pressure P to be applied on thedifferential area of a compound piston comprising a head Il of largerdiameter coaxially arranged with a stem portion 01 of reduced diameterand reciprocable in coaxial stepped bores H33 and ISa. A passage I0@ isformed axially of the composite piston. Spaced cross bores IIB and lI lintersect bore Idd and terminate respectively in circumferential grooveslilla and lila. When the composite piston is midway of its axial pcsi- Ytion in the stepped bores, groove IIOa is spaced from and covered by theinnermost end of bore Itc and groove I I Ia is spaced from and coveredby the opposite end of this portion of the bore.

The lower face of piston Hit is in continuous communication with passage|04 through conduit |05. As the full area of piston |55 bears to thedifferential area exposed to full fuel pressure P the ratio of 3:2 thepressure applied on the upper face of piston 105 will be %P.

If, by reason of insufficient volume of fuel under pressure 2/3P thecomposite piston moves too far upwardly, groove Illia will be uncoveredat the upper edge of bore 10aa. The communication thus established willenable the deficiency to be made up by fuel passing through bores IIIland |09. If there should be an excess of fuel under pressure VSP grooveIlla will be uncovered at the lower edge of bore yI 08a. and the excesswill pass through bores |09 and III, into recess I I3 and may bereturned to the fuel tank via conduit I I4.

In such a system it is not unknown, under conditions of long injectionconduits l5 of large diameter and more particularly if the tubing wallsare thin and resilient, for a very small quantity of fuel to be injectedupon decrease of pressure in conduit 1 even though this reduction shouldoccur after the remote end of conduit 5 had previously Ibeen closed tofuel pressure as by a valve 30. This is because of the release ofpressure energy stored elastically in conduits. The quantity of fuelwhich is injected in this way may be progressively reduced by increasingthe intermediate pressure which, according to the present example, is2/3P. Obviously, according to the present example, as this pressureapproaches 4/5P the force tending to lift plungers 4 upon reduction ofpressure in conduits 1, as at event A in Fig. 2, approaches zero and ifthe intermediate pressure available for application to conduits 1 byvalves I6 becomes anything in excess of %P the valves 3 in the injectionnozzles will not be opened.

The intermediate pressure may be influenced in the increasing directionby applying an upwardly acting force as on the extension Ila of thecomposite piston I 06, |01. As this method of completely eliminating allpossibility of fuel injection from the nozzles becomes useful only whendesiring to completely stop the associated engine I have shown a cam II5 and control means I I 5a by which stem IIl'Ia may be raised untilfull pressure fuel passes through groove Illia, bores I lll and IDQ toequalize hydraulic pressures on either side of piston |06. When this isdone full pressure P is supplied continuously on conduits 'I byequalizing pressures between passages I8 and I8c. This will insureagainst the possibility that any pressure which can be applied oninjection conduits 5 will Ibe adequate to lift valve plungers 4.Transiently, while lifting member I'la, resistance to motion will beexperienced due to the body of fuel trapped above piston IUE. As apractical matter this is of little or no consequence as the liftingforce itself increases the intermediate pressure toward, or perhaps inexcess of, the full pressure P. Even under unusual conditions ofelasticity in theinjection conduits 5 such a resulting' increase of theintermediate pressure need persist only for a few seconds to stop allinjection of fuel and enable the associated engine to come to rest fromthat minimum speed which is obtainable by causing event B (Fig. 2) tooccur before event A as inuenced by control means 40 (Fig. l). "Suchnormal mnimum injection, even under aggravated conditions probably willbe less than sufficient to maintain engine idling speed.

It is to be understood that the means here described for obtaining anintermediate pressure proportionally related to the full fuel pressuremay be replaced by other known pressure regulator means suitable tomaintain the pressure relations of the present example.

Only one injection nozzle 4 with its -controlling valves I6 and 30 havebeen shown. I have however indicated the conduits 5 and l for con- 7nection to additional injection nozzles 2, 3 and 4 as in a systemadapted for use with a four cylinder engine.

The sequence of operation of the injection valve I is as follows:

At the end of injection flow to the lower face of the valve is cut offby raising the plunger IB associated with the injection valve. Fullpressure is next applied through line H2 to the top of the valve byfurther raising the plunger I6 which has no effect on the movement ofthe valve. Full pressure is restored beneath the valve by loweringplunger 30 which also has no effect on the movement of the valve.Injection is then started by raising plunger I6 to reduce pressure onthe top of the valve by connecting the space at the top of the valve toline I I2 which allows the valve to lift.

I claim:

l. In a fuel injection system for internal combustion engines, incombination, an injection nozzle, a nozzle valve movable toward open orclosed position by unbalance of hydraulic pressures cyclically andopposedly applied thereon, first reciprocable valve means foralternatively and sequentially applying full fuel injection pressure anda fractional intermediate pressure to urge said valve toward a closedposition, means for reciprocating said first valve means, secondreciprocable valve means for alternatively and sequentially admittingand preventing admission of fuel at full injection pressure to urge saidnozzle valve toward its open position, means for reciprocating saidsecond valve means, and means for altering the phase relations of thecyclical reciprocations of said rst and second reciprocable valve means.

2. In a fuel injection ysystem for internal combustion engines, incombination, an injection nozzle, a nozzle valve movable toward open orclosed position by unbalance of hydraulic pressures cyclically andopposedly applied thereon, first reciprocable valve means foralternatively and sequentially applying full fuel injection pressure anda fractional intermediate pressure to urge said valve toward a closedposition, means for reciprocating said first valve means, secondreciprocable valve means for alternatively and sequentially admittingand preventing admission of fuel at full injection pressure to urge saidnozzle valve toward its open position and means for reciprocating saidsecond valve means, means for altering the phase relations of thecyclical reciprocations of said rst and second reciprocable valve means,and additional means effective at will simultaneously to alter thetiming of cyclical events of both said first and second valve means inrelation to any reference point in the cycle of an associated enginewithout altering the cycle of alternations accomplished by either saidrst or second reciprocable valves and without altering the phaserelation of complete cycles of events performed respectively by said rstand said second reciprocable valves in their relations one to the other.

3. In a fuel injection system including a fuel injection nozzle valvemovable alternatively to an open or closed position by unbalance of tworelated hydraulic pressures both greater than zero opposedly appliedthereto, a source of fuel at the pressure applied on said nozzle valveduring injection, a source of fuel at a lesser intermediate pressure ofmagnitude predeterminedly related to said first pressure and suppliedfrom said rst source, means for deriving the fuel of said second sourcefrom said first source including in ccmbination, a housing formed with astepped bore of two diameters, a compound piston of two like diametersslidable in said stepped bore, means for closing the end of said majorbore to enclose said piston in said housing and to dene a fluid chamberbetween the major diameter of said piston and the end thus closed, aconduit for passing fluid at said intermediate pressure from or intosaid chamber, a second chamber dened between the step in the bore andthe major piston diameter and defining an annular differential pistonarea less than and opposed to the major area of said piston, a conduitcontinuously communicating said second chamber to the source of fuelunder full pressure, means regulated by reciprocation of said pistonwhereby upon approaching the extremity of its movement in the directionof its major face fuel is admitted from the second said chamber to theiirst said chamber and upon approaching the extremity of its movement inthe opposite direction fuel is released from the piston face of majorarea.

4. In a fuel injection system including a fuel injection nozzle valvemovable alternatively to an open or closed position by imbalance or tivorelated hydraulic pressures both greater than zero opposedly appliedthereto, a source of fuel at the pressure applied on said nozzle valveduring injection, a source of fuel at a lesser intermediate pressure ofmagnitude predeterminedly related to said first pressure and suppliedfrom said first source, means for deriving the fuel of said secondsource from said rst source including in combination, a housing formedwith a stepped boi-e of two diameters, a compound piston of tvso likediameters slidable in said stepped bore, means for closing the end ofsaid major bore to enclose said piston in said housing and to dene aiiuid chamber between the major diameter of said piston and the end thusclosed, a conduit for passing fiuid at said intermediate pressure fromor into said chamber, a second chamber defined between the step in thebore and the major piston diameter and defining an annular differentialpiston area less than and opposed to the major area of said piston, aconduit continuously communicating said second chamber to the source offuel under full pressure, means regulated by reciprocation of saidpiston whereby upon approaching the extremity of its movement in thedirection of its major face fuel is admitted from the second saidchamber to the rst said chamber and upon approaching the extremity ofits movement in the opposite direction fuel is released from the pistonface of major area and means for applying at will an additional forceurging said compound piston to move in the direction of its major faceto increase the magnitude of Said intermediate pressure to that extentdetermined by said additional force.

5. In a fuel injection system for internal combustion engines, incombination, an injection nozzle, a nozzle valve movable tov/ard openoi' closed position by unbalance of hydraulic pressures cyclically andopposedly applied thereon, a plurality of reciprocable valve means foralternatively and sequentially applying full fuel injection pressure anda fractional intermediate prossure to urge said valve toward a closedposition, and a like plurality of second reciprocable valves 1naccordance with the number of cylinders of an associated engine andmeans to reciprocate each of said reciprocable valves in suitably timedrolation with the reciprocation of the piston iii the associated enginecylinder for alternatively and 9 sequentially admitting and preventingadmission of fuel at full injection pressure to urge said nozzle valvetoward its open position and means for reciprocating said second valvemeans, means for altering the phase relations of the cyclicalreciprocations of said rst and second reciprocable valve means, andadditional means effective at will simultaneously to alter the timing ofcyclical events of both said first and second valve means in relation toany reference point in the cycle of an associated engine withoutaltering the cycle of alternations accomplished by either said rst orsecond reciprocable valves and without altering the phase relation ofcomplete cycles of events performed respectively by said rst and saidsecond reciprocable valves in their relations one to the other.

6. In a fuel injection system for internal combustion engines, incombination, an injection nozzle, a nozzle valve movable toward open orclosed position by unbalance of hydraulic pressures cyclically andopposedly applied thereon, a plurality of reciprocable valve means foralternatively and sequentially applying full fuel injection pressure anda fractional intermediate pressure to urge said valve toward a closedposition, and a like plurality of second reciprocable valves inaccordance with the number of cylinders of an associated engine andmeans to reciprocate each of said reciprocable valves in suitably timedrelation with the reciprocation of the piston in the associated enginecylinder for alternatively and sequentially admitting and preventingadmission of fuel at full injection pressure to urge said nozzle valvetoward its open position and means for reciprocating said second valvemeans and adjustable means for altering minutely the relation of thetiming of the occurrence of a given valving event of one of said rstreciprocable valve means in relation to the piston of its associatedcylinder without altering the timing of others of said iirstreciprocable valves in relation to their respective associated enginepistons.

7. In a fuel injection system for internal combustion engines, incombination, an injection nozzle, a nozzle valve movable toward open orclosed position by unbalance of hydraulic pressures cyclically andopposedly applied thereon, a plurality of reciprocable valve means foralternatively and sequentially applying full fuel injection pressure anda fractional intermediate pressure to urge said valve toward a closedposition, and a like plurality of second reciprocable valves inaccordance with the number of cylinders of an associated engine andmeans to reciprocate each of said reciprocable valves in suitably timedrelation With the reciprocation of the piston in the associated enginecylinder for alternatively and sequentially admitting and preventingadmission of fuel at full injection pressure to urge said nozzle valvetoward its open position, means for reciprocating said second valvemeans, and means for altering the phase relations of the cyclicalreciprocations of said first and second reciprocable valve means, andadjustable means for altering minutely the relation of the timing of theoccurrence of a given valving event of one of said rst reciprocablevalve means in relation to the piston of its associated cylinder Withoutaltering the timing of said rst reciprocable valves in relation to theirassociated engine pistons.

8. In a fuel injection system for internal combustion engines, incombination, an injection nozzle, a nozzle Valve movable toward open orclosed position by unbalance of hydraulic pressures cyclically andopposedly applied thereon, a plurality of reciprocable valve means foralternatively and sequentially applying full fuel injection pressure anda fractional intermediate pressure to urge said valve toward a closedposition, and a like plurality of second reciprocable valves inaccordance with the number of cylinders of an associated engine andmeans to reciprocate each of said reciprocable valves in suitably timedrelation with the reciprocation of the piston in the associated enginecylinder for alternatively and sequentially admitting and preventingadmission of fuel at full injection pressure to urge said nozzle valvetoward its open position and means for reciprocating said second valvemeans, means for altering the phase relations of the cyclicalreciprocations of said first and second reciprocable valve means, andadditional means effective at will simultaneously to alter the timing ofcyclical events of both said rst and second'valve means in relation toany reference point in the cycle of an associated engine Withoutaltering the cycle of alternations accomplished by either said rst orsecond reciprocable valves and without altering the phase relation ofcomplete cycles of events performed respectively by said rst and saidsecond reciprocable valves in their relations one to the other andadjustable means for altering minutely the relation of the timing of theoccurrence of a given valving event of one of said first reciprocablevalve means in relation to the piston of its associated cylinder withoutaltering the timing of others of said rst reciprocable valves inrelation to their respective associated engine pistons.

CARROLL R. ALDEN.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 1,691,302 Peterson Nov. 13, 1928 1,843,410 Von Salis Feb. 2,1932 2,069,744 Alden Feb. 9, 1937 2,173,812 Bischof Sept. 19, 19392,458,294 Parker Jan. 4, 1949

